Canon today has unveiled the EOS 30D, a refined version of the EOS 20D that shares the same image sensor and numerous other core camera components but adds a 2.5-inch (diagonal) rear LCD, increased burst depth, Picture Styles, a shutter with a higher duty cycle rating and a long list of other camera usability changes.

If you're familiar with how Canon evolved the EOS-1D Mark II into the EOS-1D Mark II N, then you have a pretty good idea of the type and magnitude of tweaks the company made in updating the 20D to 30D status. The 20D has been our favourite second-body camera since its introduction in the fall of 2004, and the 30D appears to be making a good thing better.

Let's start with what's not new: the features in the 20D and 30D that are the same or similar include the 8.19 million image pixel CMOS sensor, 9-point AF system (controlled by a revised autofocus algorithm), 35-zone ambient/flash metering, 5 fps maximum shooting rate (the shutter itself is a reworked version of the one in the 20D), E-TTL II flash exposure control, built-in popup flash, 1/8000 top shutter speed, standard top flash sync of 1/250 and compatibility with 20D accessories such as Battery Grip BG-E2 (it's also compatible with Wireless File Transmitter WFT-E1/E1A and Data Verification Kit DVK-E2). The 30D's body is a close cousin to the 20D too, though changes have been made to accommodate the larger rear LCD, add a dedicated direct print/image transfer button and improve the function of the multicontroller.

Canon EOS 30D (Photo courtesy Canon)

Where the two diverge is mostly in the details. Changes in the 30D include:

The ability, like several more-pricey Canon digital SLRs, to simultaneously apply long exposure noise processing to one picture while capturing another

The addition of a 3.5% spot metering mode

0.15 second camera startup time

A more-precise 4-increment battery charge indicator

Reduced energy consumption, for a promised improvement of 10% more frames per charge

No more new folders created every 100 photos; in the 30D, a folder can hold 9999 photos

A new automatic rotation option that enables verticals to not be rotated on the rear LCD but appear rotated in compatible browser software on the computer

The ability to zoom in on a photo in Quick Review mode

During playback, the photo+shooting data screen will display file size, either an RGB or Brightness histogram and will optionally display AF markings

Improved Jump function

Refined multicontroller (both its physical design and its operation have been tweaked)

More-detailed error code information, which now appears on the rear LCD monitor (in addition to the top LCD panel); the camera settings information screen will also display Images Failed to Transfer when the WFT-E1/E1A is in use and a transmit error occurs

More ways to wake the camera up from an Auto Power Off snooze

Direct image transfer from the camera to a computer using the PTP protocol